The most common form of closure mechanism for a shoe is a lace, criss-crossing between the medial and lateral portions of the shoe upper, that is pulled tight around the instep of the foot and tied in a knot by the wearer. While simple and practical in functionality, shoelaces need to be tied by hand and often retied as they naturally loosen around the wearer's foot. Young children who have not yet learned to tie a knot require assistance from an attentive parent or caregiver. Elderly people with arthritic hands may find it difficult to pull shoelaces tight and tie knots in order to secure the shoes on their feet. People with arthritic backs, hips, knees or feet may find it difficult to bend over enough or move the affected lower extremity joint enough to put on or take off footwear or to tie shoes. Obese or handicapped people may have similar issues. Diabetic patients and patients with peripheral vascular disease need to be careful not to put on footwear that is too tight causing problems leading to diabetic ulcers, skin breakdown and loss of limb. The general population desires shoe, sneaker, or footwear that is comfortable, easy to apply and remove, and does not require adjustment once it is on the foot.
In order to alleviate problems associated with putting on shoes and other footwear and tying laces, shoes for children and adults have been provided with Velcro® hook-and-loop straps in lieu of the shoelaces. Such shoes require a user to grasp a strap secured to one end of the shoe and fasten to a complimentary Velcro® hook-and-loop patch secured to the other side of the shoe in order to close the shoes.
Both of the above shoe closure mechanisms require the use of at least one hand to hold a shoelace or a strap to close a shoe. Neither of them allow automatic adjustment of the fitting of a shoe which may become loose during wearing as a result of a person's daily activities.
A footwear with a tensioning system for automatically lacing, tightening or loosening a shoe on a foot has been reported.
U.S. Pat. No. 6,598,322 discloses a shoe having at least one elongated shape memory alloy element in the upper part of the shoe and an electric circuit which when energized will produce a tightening of the shoe upper around the foot of a wearer. A battery contained in the shoe provides a power source to produce a current in the circuit that heats the shape memory alloy and causes the shape memory alloy to reduce its length, resulting in tightening of the shoe uppers.
U.S. Pat. No. 7,310,895 provides golf shoes which include at least one sensor, a controller, and at least one active-response element. The sensor and the controller operate to rapidly determine if a golfer is walking or swinging a golf club. Once the determination is made, the controller and active-response element rapidly and automatically change the shoe's characteristics by adjusting the sole, lace, and/or upper part.
U.S. Pat. No. 8,769,844 is directed to an automatic lacing system for footwear in response to sensed information. The automatic lacing system provides a set of straps which are engaged with motors and which can be automatically opened and closed to switch between a loosened and a tightened position of the upper by the movement of the motors.
U.S. Pat. No. 8,935,860 is directed to footwear which sets itself to a customized, desired contour fit when a wearer's foot is inserted. According to the invention, there is a pressure sensor tucked away in the heel of the shoe along with a memory chip which stores the desired fit—that is, the tension on the shoe straps. The tension on the shoe straps is adjustable by one strap tightener. The strap tightener may be an electric motor powered by the battery. Alternatively, the strap tightener may be made of elongated shape memory alloy elements, which, when energized by an electric circuit, deform and tighten the shoelaces.
Despite the above self-adjusting footwear in the art, there is still a need to provide an improved footwear for hands-free operation. Preferably, the footwear is able to self-close its shoe upper when a wearer puts his/her foot into the footwear and further secure the closure with a securing mechanism. More preferably, the footwear is able to automatically adjust the fit of the footwear to a preset level of tightness upon the initial closure and also during a course of daily activities. Even more preferably, the footwear is able to automatically loosen and open for release of the foot upon receiving a signal.